Cut potatoes lengthwise into thick wedges; place in 13- x 9-inch (3 L) baking dish.
Whisk together water, lemon juice, oil, garlic, salt, oregano and pepper; pour over potatoes, turning to coat evenly.
Bake in 325Ã‚Â°F (160Ã‚Â°C) oven, gently turning occasionally to keep potatoes well moistened, for about 2 hours or until potatoes are very tender and most of the liquid has evaporated.